"21st Century's Fox's previous and ongoing payments to Mr. Shine of millions of dollars in severance payments raise questions about his compliance with federal conflict of interest statutes and regulations," the senators wrote in a letter sent Monday.

On Nov. 23, the day after Thanksgiving, the White House revealed that communications director Bill Shine received an $8.4 million severance from his former employer, 21st Century Fox, and will receive $3.5 million in additional compensation both this year and next. Now, four Democratic members of the U.S. Senate want answers about whether these payments violate White House ethics rules, considering that he might have a financial incentive to promote his former company while serving in public office.

"21st Century's Fox's previous and ongoing payments to Mr. Shine of millions of dollars in severance payments raise questions about his compliance with federal conflict of interest statutes and regulations," wrote Sens. Elizabeth Warren, Richard Blumenthal, Edward Markey and Sheldon Whitehouse in a letter sent to acting White House counsel Emmet T. Flood on Monday (first reported by CNBC and then provided to The Hollywood Reporter).

The senators asked Flood five questions about Shine that they want answered by Jan. 2.

"Mr. Shine has received two waivers from ethics rules and pledges, but neither appears to cover all of his potential violations of ethics rules and regulations," the senators wrote. "The White House Counsel in July 2018 provided Mr. Shine with an authorization to participate in matters involving his former employer, Fox News, under 5 CFR 2635.502, permitting Mr. Shine to participate in certain matters where a reasonable observer could have impartiality concerns. The waiver, however, does not address the slew of additional ethics concerns created by Mr. Shine's multimillion-dollar 'Severance Agreement' under federal statutes and regulations banning financial conflicts, supplementation of income, and extraordinary payments (18 U.S.C § 208, 18 U.S.C. § 209, and 5 CFR 2635.503)."

Shine and the White House did not comment after the U.S. Office of Government Ethics released Shine's financial disclosure report on Friday, Nov. 23. The review was signed by Shine on Oct. 9, even though the form was intended to be filed within 30 days of his start date, which was July 5 (though press reports indicated that he began earlier than that).

It's not clear whether Flood will respond to the letter, which is a request for more information rather than a threat of legal or congressional action (the Democrats will remain the minority party in the U.S. Senate when the new term begins).

The senators, however, conveyed the seriousness of potential wrongdoing: "Federal officials who violate federal conflict of interest law may be subject to civil or criminal penalties."

The lawmakers also questioned the size of Shine's payout from 21st Century Fox, the parent company of the cable network he helped run, Fox News. The question is whether Shine's payment would qualify as "extraordinary," and whether 21st Century Fox knew that Shine was being considered for a job in the Trump administration when it made the payment.

Among other things, the senators want a list of meetings and communications Shine has had with "with current employees of 21st Century Fox, Fox News Channel, and its affiliates."

They also want to know if the White House made "any ethics determinations" stemming from the revelation that Shine would receive compensation from 21st Century Fox even while serving in the executive branch. "If so, please provide copies of any determinations, ethics guidance, or ethics advice regarding Mr. Shine's continued payments from 21st Century Fox," they wrote.